The present invention relates to an electrical test probe suitable for use in an electrical test of a plurality of semiconductor integrated circuits formed on a semiconductor wafer and a prove assembly into which this probe is incorporated.
A plurality of semiconductor integrated circuits formed on a semiconductor wafer generally undergo an electrical test before being separated into respective chips to determine whether or not they are manufactured in accordance with the specification. In this electrical test is used a probe assembly comprising electrical test probes to be connected to electrodes of devices under test, that is, the respective semiconductor integrated circuits. The devices under test are connected to a tester via this probe assembly.
One of the conventional probes used for this probe assembly is one comprising a plate-shaped probe main body portion and a probe tip portion provided on the probe main body portion to contact an electrode of a device under test (for example, refer to International PCT Publication WO2006/075408, hereinafter “Patent Document 1”). The probe main body portion has an attachment portion to a probe board, a pair of arm portions extending from the attachment portion to the lower side of the probe board laterally along the probe board with a space from the probe board, and a pedestal portion formed integrally with the arm portions so as to combine the ends of the both arm portions, and the aforementioned probe tip portion is provided on the pedestal portion. According to Patent Document 1, it is proposed that the probe main body portion should be made of a highly flexible or tough conductive material, and the probe tip portion provided at the lower end of the pedestal portion of the probe main body portion should be made of a metal material with excellent hardness.
By making the probe main body portion of the highly tough metal material, elastic deformation of the arm portions of the probe main body portion is enhanced when the probe tip portion of the probe is thrust upon the electrode of the device under test, which enables the probe tip portion to connect the electrode appropriately and reliably. Also, when an overdrive force that causes the aforementioned elastic deformation at the arm portions of the probe acts on the probe, the tip of the probe tip portion slides on the electrode along with the elastic deformation of the arm portions. By forming this probe tip portion by the highly hard material, abrasion of the tip is suppressed, and decrease in durability of the probe caused by the abrasion is prevented.
Meanwhile, in a case where one wafer surface is divided into plural chip areas, and an electrical test is performed per divided area by using the conventional probe assembly, the tips of some probes that deviate from the chip area may sometimes contact the tilting edge of the wafer in a state where the overdrive force acts on the probes. In such a case, when the tips are guided outward along the tilting edge of the wafer, a bending force acts on the probe tip portions of the probes. Also, when the tip of the probe contacts the edge of the opening edge portion, which exposes the electrode, of the passivation film covering the surface of the semiconductor wafer, the similar bending force may act on the probe tip portion. Since these bending forces may cause breakage of the probe tip portion made of the highly hard material, it has been desired that the probe tip portion should be reinforced against such bending forces.
Also, as the fine probe tip portion protruded from the lower surface of the pedestal portion is made of the highly hard metal material, the fragility of the probe tip portion may cause defect or breakage when a load is applied to the tip of the probe tip portion. Thus, it has been desired that the defect or breakage of the probe tip portion should be reliably prevented.
Patent Document 1: International Publication WO2006/075408